1. Field of the Invention
This invention relates to employing a soft particulate abrasive in a fluid stream for removing soft tooth decay from a tooth.
2. Background Discussion
Using abrasives carried in a fluid stream to remove material in a precise manner is not new. Kirschner U.S. Pat. No. 5,160,547 discloses an air abrasion process for removing material from sensitive substrates in general, using sodium bicarbonate as the abrasive media. Carr U.S. Pat. No. 4,731,125 discloses an air abrasion method for cleaning paint from composite airplane panels using a plastic abrasive media. Drury U.S. Pat. No. 5,145,717 discloses an air abrasion method of resist removal in the manufacture of printed circuit boards using a plastic abrasive media.
Air abrasion in dentistry also is not new. Rzewinski U.S. Pat. No. 4,494,932 discloses an air abrasion apparatus and method for cleaning teeth, i.e., removing difficult stains and heavy plaque using an unspecified soluble powder. Karst U.S. Pat. No. 4,950,160 discloses an air abrasion instrument for polishing teeth using an unspecified abrasive powder. Finally, Goldsmith U.S. Pat. No. 5,275,561 discloses a fluid abrasion method of preparing a tooth structure, including dentin and enamel surfaces, for bonding a composite to the prepared surfaces using aluminum oxide as the abrasive material. While aluminum oxide works well as an abrasive for removal of hard caries material and on healthy tooth structure to roughen it as a pretreatment for bonding, it is inefficient in removing soft caries material from decayed tooth structure. The process of this invention provides a way to remove the soft caries material using an abrasive that is softer than aluminum oxide.